Control means



NOV. 5, 1940. 5 TURNER 2,220,743

CONTROL MEANS Filed June 3, 1939 4 Sheets-Sheet 2 jgblvENTOR MAM...

ATTORNEYS.

NOV. 5, 1940. s TURNER 2,220,743

CONTROL MEANS Filed June 3, 1939 4 Sheets-Sheet 3 ATTORNEYS Nov. 5, 1940. H. s. TURNER 2,220,743

CONTROL MEANS Filed June 3, 1939 4 Sheets-Sheet 4 INDOOR /9 RISER. Z2 T Z; I;

OUT DOOR ORANGE GREEN BUZZER Q OFF 58 INVENTCR ma! 21W BY i i ATTORNEYS Patented Nov. 5, 1940 UNITED STATES PATENT OFFICE 21 Claims.

This invention relates to control means for steam-heating systems and more especially to control means fora steam-heating system for a multi-tenanted building having a central energizing heat source.

An object of this invention is a control system which is responsive to temperature variation of the order of one-half a degree and is effective to maintain substantially uniform temperature throughout a multi-tenanted building.

A further object is a control system having signal means for indicating at a central station the heat conditions prevailing in the various rooms and also any improper conditions existing in the operation of the heating system.

An additional object is a control system which energizes an indicating signal in the event of improper conditions of water level or steam pressure in the boiler and de-energizing the heat source in the event that such conditions exceed a predetermined limit or become abnormal.

The control apparatus of this invention isintended primarily for use in connection with a steam heat system for a vmulti-tenanted building, the system including an electrically controlled heat generator such, for example, as a forced draft coal burner or an oil or gas burner andva steam boiler associated with the heat generator. In some or all of the rooms are installed thermostats designed to open and close an electrical circuit which, either by itself or in co-operation with other similar circuits regulates energization of the control apparatus to supply heat as required by the temperature conditions in the various rooms. Also, the control apparatus embodies means for discontinuing operation of the heat generator or diminishing the heat furnished in the event of the development of excess steam pressure in the boiler or in the event that the level of water in the boiler drops below or rises above predetermined levels.

Preferably, the energization of the heat source is regulated by a motor driven rotor and the motor circuit is provided with a pair of self-closing contacts normally held open by means actuated by a heat-responsive member. A heater circuit for said member isconnected in multiple with each of the thermostats which are designed for operation upon one-half degree temperature variation. The heater is so designed that closure of one or more thermostats for a predetermined length of time is required for actuation of the contact-engaging means to permit the contacts to close, thereby energizing the motor to actuate the rotor with resultant energization of the heat source. The rotor actuates means to re-engage the contact-engaging means with the contacts after a predetermined extent of operation of the rotor to open said contacts and deenergize the motor with the heat source remain- 5 ing energized. Upon temperature increase of one-half degree, the closed thermostats open with resulting de-energization of the heater in circuit therewith, whereupon the heat-responsive member returns to original position with further 10 release of said contacts into closed position to effect further rotation of the rotor to de-energize the heat source and cause re-engagement of the contact-engaging means with the contacts to open them. Momentary closure of one or 16 more room thermostats due to vibration thereof or due to another cause will not result in energization of the control apparatus, in view of the fact that it is necessary for the contacts to remain closed for a predetermined length of time 2 before the heat-responsive member can be heated sufliciently to cause release of the contacts into closed condition.

At a central station, a signal light in series with each thermostat is provided and when en- 25 ergized indicates that the temperature in the location of such thermostat has dropped below the thermostat setting. Also, associated with the heat source is a signal light which, when energized, indicates that heat is being supplied to 30 the boiler.

In addition, signal means are provided for indicating improper conditions of water level or steam pressure in the boiler. Such signal means comprise a light and a buzzer which are inter- 5 mittently operated when steam pressure or water level in the boiler varies slightly from predetermined limits. Upon restoration ofproper conditions either by the attendant or by operation of the system itself, such signal means becomes 40 inoperative. However, in the event that such improper conditions exceed a predetermined limit, the signal becomes steady and simultaneously the heat source is de-energized. In the latter' case manual resetting of the device is necessary, 5 which can only be done after the steam pressure or water level has been brought back to normal.

Other objects, novel features and advantages of this invention will become apparent from the following specification and accompanying draw- 50 ings, wherein:

1 is a, front elevation of a control apparatus embodying the invention;

Fig. 2 is a side elevation;

Fig. 3 is a plan view; 55

Fig. 4 is a view generally similar to Fig. 2 free end of the thermostat strip 32 and is adaptshowing a different condition of the parts;

Figs. 5'. 6, 7. and 8 are sectional views substantially on the line 5-5 of Fig. 2 illustrating the operation of certain parts of the device;

Fig. 9 is a perspective view of the contact-controlling apparatus; Y

Figs. 10 and 11 are sectional views substantially on the line Ill-l3 of Fig. 2 showing different-operating positions of certain parts;

Fig. 12 is a front elevation of Fig. 10;

Fig. 13 is a perspective view of the mechanism illustrated in Fig. 12, and

Fig. 14 is a wiring diagram.

As shown in Figs. 1 and 2, a motor i3 is supported by a suitable bracket H from a panel P of electric insulating material and is provided with reduction gearing contained in the housing l2 and having a driven shaft l3. A disk I4 is eccentrically supported by the shaft i3 and an arm i5 is attached to the shaft i3. A screw i5 is received in a slot i! of the arm 45 and provides means for effecting limited arcuate adjustment of said arm. A second arm i3 is fixed to the shaft i3 and is provided with a series of holes by means of which a cable or the like may be attached to the arm at different radial distances from its axis of rotation.

A generally H-shaped bracket l3 has the upper ends of its two side members attached to the panel P and the intermediate portion of the bracket extends outwardly and downwardly from the panel with the lower ends of the side members vertically arranged. A pair of slides 23 are adjustably supported by the bracket l3 through the intermediary of screws 2| passing through slots in the slides 23 and threaded into the side members of the bracket l9, each slide being provided with an upwardly projecting lug 22. A plate 23 is supported from the bracket I! by the screws 2i and is provided with a pin 25 on which is oscillatably mounted a rocker 26 having arms 21 upturned at their ends to engage the periphcry of the disk i4.

A rider 28 of electrical insulating material is provided with a pair of slots in which are received screws 29 threaded into the side members of the bracket l9 and said slots are slightly inclined toward each other downwardly. The bottom edge of the rider 23 is engaged by 8. prong 30 forming a part of the rocker 26 and said bottom edge is so shaped as to provide a pair of oblique surfaces sloping upwardly toward the center of the rider and terminating in a second pair of short oblique surfaces sloping downwardly and connected by a horizontal portion. A recess 3| is formed in the upper portion of the rider 28, and a resilient bi-metal thermostat strip 32 is supported at one end from the panel P with its other end extending into the recess 3!. (Figs. 1 and 2).

Just below the bi-metal strip 32 is an arm 33 composed of electrical insulating material pivotaliy supported at one end by the panel P and having its other end resting on the top edge of the plate 23 between the lugs 22 which act as stops to limit swinging movement of the arm 33. The outer end of the arm 33 is forked so as to have a. portion arranged at either side of the prong 30. A contact 34 is fixed to the member 33 and a contact 35 is carried by one end of a leaf spring 36 having its other end fixed to the arm 33 and having its contact end underlying the recess in the free end of the arm 33 (Fig. 9). A prong 31 of insulating material is carried by the ed under certain conditions to enga e the free end of the leaf spring 33 to disengage the contact 35 from the contact 34. Two spring arms 33 are carried by the rocker 23 and have their ends extending into the recess in the end of the arm 33 at either side of the-prong 33 (Fig. 1).

Around the strip 32 is wound a resistance wire 33 forming a heating coil which is in circuit with a source of electrical energy (Fig. 14) and each of a plurality of room thermostats of which five are shown here and designated T1, T2, T3, T4 and Ts. The contacts 34 and 35 are connected by suitable wiring in circuit with a source of electrical energy and the motor Ill so that whenever the contacts are closed, the motor is energized (Fi 14).

The arrangement just described provides for intermittent rotation of the disk l4 and arms i5 and I3 through arcs of approximately With the parts in the position shown in Figs. 1 and 5. the contacts 34 and 35 are open and the motor is de-energized, and all the room thermostats are open. Now assume that a room thermostat closes, thereby causing the flow of current in the heating coil 33 with consequent heating of the strip 32. The strip is warped to move its end to the left (Fig. 6) suiliciently to disengage the prong 31 from the left edge of the spring 36. thereby resulting in closing of the contacts 35 and 38 with consequent energization of the motor i5. Operation of the motor causes counterclockwise rotation of the shaft H which in turn causes the rocker 23 to swing counterclockwise, to a degree depending upon the eccentricity and diameter of the disk l4 (Fig. 1). The prong 33 slides along the bottom edge of the rider 23 elevating it, together with the free end of the strip 32 sufilciently for the prong 3! to clear the spring 35 and then dropping the rider and strip. At the same time, the left hand spring 33 engages the left prong of the arm 33 to move it to the left, such movement being permitted due to the fact that the prong 31 has been elevated. The extent of movement of the free end of the arm 33 is sufficient to locate the free end of the spring 33 under the prong 31 so that when it is dropped, it opens the contacts 34 and 35 (Fig. 7). The timing is such that the contacts 34 and 35 are opened after the disk l4 has completed one-half revolution.

The contacts 34 and 35 are held out of contact so long as the strip 32 is maintained in warped position by heat generated in the heating coil 39. Discontinuance of the flow of current through the coil 39 as by opening of a thermostat results in the strip 32 returning to original temperature and position which will cause the prong 3'! to slip off the right edge of the spring 33, thereby again energizing the motor N) (Fig. 8). Thereupon, the above-described sequence of operations is repeated except that the rocker 25 moves clockwise and the free end of the arm 33 is moved from left to right. The timing is so arranged that the contacts 34 and 35 are again opened when the disk [4 returns to original position.

A carrier 43 for a mercury switch 43a is pivotally supported by a pin 4| carried by a lever 42 pivotally supported by a pin 43 carried by a bracket 44, the inner end of which is attached to the panel P. The carrier 43 has a spring blade 45 extending into the path of the arm I 5. As the arm i5 approaches the position shown in Fig. 1, it engages the blade 45 to lift the mercury switch into open position and to hold it in open position so long as the arm 15 remains substantially in the position shown in Fig. 1. As the arm I5 moves from the position shown in Fig. 1, the blade 45 yields sufllciently not to impede the movement of the arm l5 and after the arm 5 moves out of engagement with the blade 45, the mercury switch drops by gravity into closed position, and remains in closed position until it is again elevated by the arm l5.

In circuit with the mercury switch is an electrically controlled heat generator including, for example, a motor-driven oil burner or coal furnace blower and to the arm I8 is attached a cable or the like for controlling the operation of dampers associated with said heat generator or for performing any other required mechanical movement. Thus, whenever the mercury switch is in closed position, the heat generator is energized to supply heat to the areas in which are arranged the thermostats T1 to T5. As long as the temperature in the areas in which the thermostats are arranged is above the temperature at which the thermostats are set to close, the control apparatus remains in the position shown in Fig. 1 with the mercury switch held in elevated or open position by the arm l5 and the prong 31 engaged with the spring 35 to keep the contacts 34 and 35 in open position. When the temperature at any thermostat drops to the temperature at which such thermostat is set to close, the closing of said thermostat causes the now of current in heating coil 39 with consequent heating of the strip 32 andmovement of its free end to the left to cause the prong 31 to slide 011 the left edge of the spring 35 with consequent closing of the contacts 34 and 35. The motor is then energized to rotate the disk l4 and after it has been rotated through an arc of approximately 180 it comes to rest as previously described with the prong 31 engaged with the spring 35 of the strip 32 in warped condition to open the contacts 34 and 35. Such rotation of the disk disengages the arm l5 from the plate 45 with consequent dropping of the mercury switch 40 into closed position to set in operation the heat generator.

The elements remain in the position last described until after the thermostats open due to temperature increase with consequent interruption of current flow through the heating coil 39, thus allowing the strip 32 to cool and return to original position. The movement of the end of the strip 32 to the right causes the prong 31 to slide on the right edge of the spring 35 to permit closure of the contacts 34 and 35 to again energize the motor which rotates the disk l4 again through an arc of approximately 180 to return the various parts to the position shown in Fig. 1 with consequent raising of the mercury switch to open position and de-energization of the heat generator.

A bracket 45 has different elevation horizontal parts supported by the panel P and brace 45a. and a cradle 41 is pivotally supported by the bracket (Fig. 1). A pipe 48 is rigidly supported on the cradle 41 by a clamp 49 and is provided with terminal fittings 58 and 5|. The lower and open end of a hollow glass vessel 52 is sealed in the fitting 50 and similarly sealed in the fitting 5| is a glass tube 53 also sealed in a fitting 54 at its upper end. To one end of'the, pipe 48 is attached a flexible metal hose 55 connected by suitable means (not shown) to the boiler of the heat generator below its normal water-line. Similarly attached to the fitting 54 is a flexible metal hose 55 connected by suitable means (not shown) to the boiler above its normal water-line. The upper double angle part of the bracket 48 has attached thereto a plate 51 of electrical insulating material which carries a pair of separated contacts 58 in circuit with the heater 39 (Fig. 14). A plate 59 fixed to the cradle 41 extends upwardly behind the plate 51 and carries an insulated brush 50 for engagement with the contacts 58, the brush 50 being slotted over a. portion of its length to provide separate arms (Fig. 12). A lever 5| is pivoted by a pin 51a to the rear face of plate 59 and has a horizontal extension 52 terminating in a prong 53 and also carries a pin 54 which extends through an aperture in the plate 51 for engagement with a pair of bars 55 adjustably attached to the front face of the upper part of a bracket 45. Rocking of the cradle 41 brings the pin 84 into engagee ment with one of the two bars 55 with consequent rotation of the lever 5| relative to the plate 53 to cause lateral movement of the prong 53 to a greater extent than the lateral movement of pivot pin 5|a (Figs. 11 and 13). The extent of lateral movement of the prong 53 is determined by adjustment of the bars 85. The width of the prong 53 and the thickness of the lever 55 is such as to permit a substantial amount of movement of the prong 53 without disengaging it from the lever 55.

A vertically arranged lever 55 is pivotally supported on the lever 42 by a pin 51 and its upper end extends into a recess formed in one end of a horizontal lever 58 pivotally supported by the bracket l9 (Fig. 3). The lever 58 is equipped with an arm 53 having a prong 15 of electrical insulating material adapted under certain circumstances to engage the freeend of the strip 32 either to return it to or maintain it in its extreme right position, thus either causing operation of the motor to return'the parts to the position shown in Fig. 1 or preventing operation iof the motor to move the parts from such posiion.

The lever 55 is so arranged as to have its lower end in register with the prong 53 when the cradle 41 is in such position that the major portion of the pipe 48 is horizontal and to have such lower end urged by gravity into contact with the prong 53. In such position of the lever 55, its upper end so locates the lever 58 that the prong 18 is out of engagement with the strip 32'. However, in the event that the cradle 41 is tilted sufllciently either to the right or the left to effect liisengagement of the prong 53 from the lever 55,

then the lower end of the lever swings forward and the upper end swings rearwardly with consequent operation of the lever 58 to bring the prong 15 into contact wtih the strip 32, either to return the free end thereof to its extreme right position if warped out of such position by flow .of current through heating coil 39 orto hold it the contact 13 but normally an adjusting screw 15a on the free end of the insulated arm 15 carried by the upper end of the lever 55 maintains the leaf spring in such position that the contacts II and 14 are out of engagement except when the strip H is sumciently warped by heat supplied thereto from the heating coil 12 to eiiect engagement of the contact" with the contact 14 or when lever 85 takes the position shown in Fig. 4. The heating coil 12 is shunted around the contacts 58 and is in series with the heating coil 88 which is of much lower resistance. So long as the circuit of the coil 38 is closed through contacts 58 and brush 58, the heating coil I2 is de-energized. The contacts I3 and 14, when engaged, close a low resistance shunt circuit around the heating coil 12, such shunt circuit including signal means consisting of a buzzer B and a red light Ln. Upon rocking oi the cradle 41 in either direction suflicient to disengage the brush 50 from one contact 58, the short-circuit around the heating coil 12 is opened, thus causing current flow through the heating coil 12 with consequent energization thereof. Heating oi the strip Ii clue to energization of the coil 12 causes the strip to warp suiiiciently to engage the contact 18 with the contact 14 thereby causing current flow through the shunt circuit including the buzzer B and red light In with consequent energization of said signal means.

The closing of the signal energizing circuit reduces the current flow through the heater 12 with consequent cooling of the strip II to disengage the contact 13 from the contact I4 thereby opening the signal circuit to interrupt the operation of the signal. Current flow is then re-established through the heating coil 12 to repeat the cycle above described and such repetition of the cycle is continued so long as the brush 80 remains out of engagement with one contact 58 and the cradle 41 is not rocked sufiiciently to disengage the prong 83 from the lever 86.

Under normal operating conditions, the level of water in the vessel 52 bears such relation to the level of water in the tube 53 so that the cradle 41 is maintained with the major portion of the pipe 48 substantially in horizontal position. Rocking oi the cradle is effected by variation in the relation of liquid levels in the vessel 52 and in the tube 53 due to the liquid level in the boiler being too high, the liquid level in the boiler being too low or the steam pressure in the boiler exceeding a predetermined limit. Ordinarily, any change in the relation of the liquid levels in the vessel 52 and the tube 53 occurs gradually and the intermittent operation of the signal means calls the attention of the attendant to the condition in time for him to remedy the condition before it becomes dangerous. However, means are provided so that in the event of a large change in the relation of the liquid levels in the vessel 52 and tube 53 due to excessive steam pressure or a boiler rupture or the like or due to failure of the attendant to rectify the condition indicated by the intermittent operation of the signaling means, the control appara-- tus will act to de-energize the heat generator or prevent its energization and simultaneously effect continuous operation of the signal means.

The means just referred to include the lever 56 and the arm I5 carried thereby. Upon a large change in the liquid levels, the cradle is rocked sumciently to disengage the prong 83 from the lever 86 whereupon the lever 66 swings to disengage the arm 15 from the end of the leaf spring 15 to allow it to move the contact 14 into engagement with the contact I3. The contact 14 will remain engaged with the contact 13 irrespective of movement of the bi-metal strip 1|, so that the signalling means are continuously energized. This produces a steady signal in La and the buzzer indicating an emergency condition of the heating plant. Also, the lever 85 swings the arm 88 to cause the prong 18 to engage the end oi the strip 32 either to move it to its extreme right position. and/or hold it in such position, thereby discontinuing operation of the heat generator.

A plunger 11 is connected to the lower end of the lever 85 for returning the lever to a position to be engaged by the prong 53. However, such engagement cannot be re-established until after the cradle is returned to normal position by proper re-arrangement of the water levels in the vessel 52 and tube 53.

- The mercury switch carrier 40 is provided with a contact 18 which engages a contact 19 carried by the panel P when the mercury switch is in closed position. These contacts are connected in series with a green signal light, the energization of which indicates that the control circuit for the heat generator is closed and that heat is being supplied.

Behind glass tube 53 is mounted a scale 80 bearing two arms 8| and 82, marked respectively "No steam and Full steam." These arms are so adjusted on each installation that their upper edges are level with the water in the tube when the connected heating system is cold and steam saturated. Contacts 58 are opened by brush 60 when the lower arm is reached, thereby shutting down the control as soon as the heating system is steam saturated, irrespective of the steam pressure involved.

In Fig. 14 are illustrated the electrical connections for the entire control system above described. The motor IO is bridged across the two wires of a 110 volt circuit in series with a snap switch and the contacts 34 and 35. The motor 80 of a blower or oil burner or an electrically controlled gas valve is connected in circuit with the contacts of the mercury switch 40. Each of the room thermostats T1, T2, T3, T4 and T5 and the indoor riser thermostat Te has one terminal connected to a bus bar B. B. which is connected to the terminal T of the secondary of a step-down transformer T, the primary of which is bridged across a 110 volt line. From the remaining terminal T of said secondary, a first circuit may be traced to the right contact 58, through the brush 60 to the left contact 58, thence through heating coil 39 to a switch S, then through lamps L1, L2, L3. L4, L5 and Le, in parallel, and the resistances R to the remaining terminals of the thermostats T1, T2, T3, T4, T5 and one terminal of the outdoor thermostat T1, the remaining terminal of which is connected to the remaining terminal of the thermostat To. In shunt to the contacts 58 and heating coil 39 is a second circuit comprising the heating coil 12. When the contacts I3 and I4 engage, due to warping of the strip II by heat supplied thereto from the coil 12 when energized, a third circuit is formed in shunt around the heating coil I2, this third circuit including, in addition to the contacts 13 and 14, a portion of the leaf spring l5, the bi-metai strip 'II, together with the buzzer and lamp L7, the lamp and buzzer being connected in parallel with respect to each other.

Whenever the contacts of one of the thermo-- stats T1 to T5 or the contacts of thermostats T6 and T1 are closed, and the contacts 58 are bridged by the brush 60, current flows in the heater coil 38 circuit with consequent energization of the respective lamps L1 to Le depending on which thermostats are closed. The lights thus signal to the attendant the areas calling for heat and the condition of the riser and outdoor thermostats. Under such circumstances, the heating coil 12 is de-energized. Should the brush I be moved from bridging relation to the contacts ll, thus breaking the circuit Just described, current is caused to flow through the heating coil 12, thereby generating sumcient heat to cause warping of the strip II to bring the contact 13 into engagement with the contact I4. Such engagement of these contacts closes the signal energizing circuit with consequent de-energization of the heating coil 12 due to the lower resistance of the signal circuit. De-energization oi the heating coil 12 results in cooling of the strip Ii and its consequent return to positions in which the contact 13 is disengaged from the contact 14 thereby causing re-energization of the heater coil 12 and repetition of the cycle above described. Whenever the heater 3! is de-energized by movement of the brush 60 out of bridging relation to i the contacts I! which adds the comparatively high resistance of coil 12, the strip assumes the position in which it maintains the heat source in inoperative condition due to insumcient current in the coil 39. Also, upon closing of the contacts 13 and 14 by release of the leaf spring due to movement of the member 16, the signal circuit is continuously energized. Energization of the lamp L1 to Is continues irrespective of the operations just described, so long as the correspond.- ing thermostats T1 to T5 inclusive are in closed condition.

With the contacts 18 and 19 engaged, a fourth circuit may be traced from said terminal T" through the contacts I9 and 18, through the preferably green light Ls, upper resistance R, to the bus bar B. B. and thence to the terminal T of the transformer secondary. This circuit is closed whenever the mercury switch 40 is closed and the green light indicates to the attendant that the heat generator is in operation. Any one of the thermostats and its corresponding lamp may be cut out of the circuits described by the manipulation of the switch in series therewith should occasion arise for such disconnection. Also, the lamp Lo and the thermostats To and T1 may be removed from such circuit by the operation of the switch associated therewith.

In the foregoing description, it has been assumed that the current supplied by the closing of a single room thermostat would supply suflicient energy to warp the thermostat strip 32 into position to close the motor circuit. It is contemplated that in many installations the arrangement will be such that suflicient energy to warp the thermostat strip 32 will not be supplied upon the closing of a single thermostat, but will be supplied only upon the closing of two or more thermostats. This arrangement prevents operation of the heat generator in response to an abnormal heat condition existing at only one thermostat location while suitable conditions prevail at the other thermostat locations. To facilitate this effect, each thermostat circuit is brought up to a standard electric resistance by the insertion therein of the necessary resistance R. There is no resistance added in circuit with thermostat To, consequently this thermostat actuates the control alone. This latter effect may be enhanced by placing a resistance around lamp L6, as shown. Thermostat Ts is fastened to a steam pipe at the farthest away point from the boiler. It operates to keep the heating system mildly heated at all times irrespective-of the room thermostats. T1 is placed in series with it so as to open this circuit when the weather is mild outdoors.

One of the advantages in the use of the described heat control system is that the room thermostats can be so made and adjusted as to close and open their contacts on extremely minute temperature changes of air surrounding them. For example, thermostats such as shown and described in my co-pending application, Ser. No. 272,952 may be used, such thermostat being sensitive to a temperature change of a half degree. However, if this is done eddy currents of air of slightly different temperatures, as well as mechanical vibrations, cause the contacts to open or close, when the actual average room temperatures do not so indicate. Due to the heat absorbent factor of bi-metal strip 32, this does not cause premature operation of the control, either to perform the on or off" operation; as a definite amount of heat energy from coil ll must first be absorbed by strip 32, before it can trip switch 33 controlling motor II. In practice it will be found that on a reasonably cold day the signal lights Ll-Ili will be blinking on and of! continually and that only when the on period of one, two or more lamps, according to the control adjustment, represent a time period greater than the off periods, does the control operate. Conversely, after operation, when the 01'1" periods of the lamps become longer than the "on" periods, then the control returns to the heat "off position. In each case control operation is irrespective of whether the signal lights and consequently the thermostat contacts are on steadily or remain ofi steadily or whether the lights are blinking and the thermostat contacts intermittently closing and opening.

While the description herein given has applied to heat generators it is contemplated'that by merely reversing the bi-metal element of the thermostats used, the system can be applied to air cooling, especially as the latter demands a close temperature control on account of the cost factor involved in cooling air.

I claim:

1. A control device for an attemperating system including electrically energized means for producing temperature changes in an enclosed area, said device comprising a control switch for said means supported for automatic movement into closed position, a motor driven rotatable arm adapted during each revolution to move said switch to open position and release such switch for automatic return to closed position, a motor circuit including a. pair of self-closing contacts, a carrier supporting said contacts and'movab-le between two positions, a thermostat strip supporting an insulated member and arranged upon change of its temperature to move said insulated member between two positions corresponding to the two positions of said carrier, said insulating member being adapted when it and said carrier are in corresponding positions to open said contacts, a heating circuit for said thermostat strip including one or more thermostats, means operated in timed relation to said arm for moving said carrier between its two positions, additional means operated in timed relation to said arm for moving said insulated member out of contactengaging position during movement of said carrier and releasing said insulated member for return to contact-opening position, the actua in one position of rest to hold said control switch in open position.

2. A. control device for a heating system including a boiler and an electrically energized heat source, said device comprising a heat source control switch for said means supported for automatic movement into closed position, a motor driven rotatable arm adapted during each revolution to move said switch to open position and release such switch for automatic return to closed position, a motor circuit including a pair of selfclosingcontacts, a carrier supporting said contacts and movable between two positions, a thermostat strip supporting an insulated member and arranged upon change of its temperature to move said insulated member between two positions corresponding to the two positions of said carrier, said insulating member being adapted when it and said carrier are in corresponding positions to open said contacts, a heating circuit for said thermostat strip including one or more thermostats, means operated in timed relation to said arm for moving said carrier between its two positions, additional means operated in timed relation to said arm for moving said insulated member out of contact-engaging position during movement of said carrier and releasing said insulated member for return to contact-opening position, the actuation of said insulated member and carrier being timed to stop the arm twice during each complete revolution thereof and the arm being operative in one position of rest to hold said heat source control switch in one position, and means responsive to predetermined changes of steam and water conditions within said boiler to return said insulated member to or hold said insulated member in the position assumed by it to stop said arm in open position of said control switch.

3. A control device for a heating systemincluding a boiler and an electrically energized heat source, said device comprising a heat source control switch supported for automatic movement into closed position, a motor driven rotatable arm adapted during each revolution to move said switch to open position and release such switch for automatic return to closed position, a motor circuit including a pair of self-closing contacts, a carrier supporting said contacts and movable between two positions, a thermostat strip supporting an insulated member and arranged upon change of its temperature to move 'said insulated member between two positions corresponding to the two positions oi. said carrier, said insulating member being adapted when it and said carrier are in corresponding positions to open said contacts, a heating circuit for said thermostat strip including one or more thermostats, means operated in timed relation to said arm for moving said carrier beween its two positions, additional means operated in timed relation to said arm for moving said insulated member out of contactengaging position during movement of said carrier and releasing said insulated member for return to contact-opening position, the actuation of said insulated member and carrier being timed to stop the arm twice during each complete revolution thereof and the arm being operative in one position of rest to hold said heat source conrol switch in open position, means responsive to predetermined changes of steam and water conditions within said boiler to return said insulated member to or hold said insulated member in the position assumed by it to stop said arm in open position of the heat source control switch, and signal means operated intermittently in response to slight changes of steam and water conditions inthe boiler and operated continuously in response to said predetermined changes oi. steam and water conditions.

4. In a device of the character described, an oscillatable carrier movable between two positions, a pair of co-operating self-closing contacts supported thereby for relative movement, a strip of thermostatic material supported in parallel relation to said carrier, an insulated member carried by one end or said strip and being .movable by said strip' upon change of its temperature between two positions corresponding to the two positions of said carrier, said insulated member being adapted when it and said carrier are in corresponding positions to engage one of said contacts to move it away from the other contact, means for effecting change of temperature of said thermostatic strip, a motor having said contacts in its energizing circuit, means actuated by said motor to move said carrier between its two positions, to lift said member out of engaging relation to said one contact and to release said member for engagement with said contact.

5. 'In a device 01' the character described, an oscillatable carrier movable between two positions, 8. pair of co-operating self-closing contacts supported thereby for relative movement, a strip of thermostatic material supported in parallel relation to said carrier, an insulated member carried by one end or said strip and being movable by said strip upon change oi its temperature between two positions corresponding to the two positions of said carrier, said insulated member being adapted when it and said carrier are in corresponding positions to engage one of said contacts to move it away from the other contact, means for effecting change of temperature of said thermostatic strip, a motor having said contacts in its energizing circuit, a pivoted rocker connected to said motor for oscillation thereby and connected to said carrier to eiifect oscillation thereof, a movable rider engaging one end oi said strip and being supported for automatic movement toward the axis 01' said rocker and for movement by said rocker away from the axis thereof to move said insulating member out of engaging relation to said one contact.

6. In a device of the character described, an oscillatable carrier movable between two positions, 9. pair of co-operating self-closing contacts supported thereby for relative movement, a strip of thermostatic material supported in parallel relation to said carrier, an insulated member carried by one end 01' said strip and being movable by said strip upon change of its temperature between two positions corresponding to the two positions of said carrier, said insulated member being adapted when it and said carrier are in corresponding positions to engage one of said contacts to move it away from the other contact, means for effecting change of temperature of said thermostatic strip, a motor having .said contacts in its energizing circuit, an eccentric disk driven by said motor, a pivoted rocker connected 7 matic movement toward the axis of said rocker 1s and for movement by said rocker away from the axis thereof to lift said insulating member out of engaging relation to said one contact.

7. In a device of the character described, a carrier horizontally oscillatable between two positions and having a cut-out portion at its free end, a leaf spring fixed at one end to said carrier and having its other end in register with said cut-out portion, co-oper'ating contacts carried by said carrier and said leaf spring, a strip of resilient thermostatic material supported in parallel relation to said carrier, an insulated member carried by said strip and being movable by said strip upon change or its temperature between two positions corresponding to the two positions of said carrier, said insulated member being adapted when it and said carrier are in corresponding positions to engage said leaf spring to separate said contacts, means for eflecting change of temperature oi! said thermostatic strip, a motor having said contacts in its energizing circuit, a pivoted rocker having a prong extending into the cutout portion of said carrier and being connected to said motor for oscillation thereby, spring arms carried by said rocker and extending into said cut-out portion, a vertically movable rider engaging the end of said thermostatic strip and being engageable by said prong to lift said insulated member in timed relation with horizontal movement of said carrier.

8. In a control device for a heating system including a boiler and an electrically energized heat source, a resilient thermostat strip fixed at one end, means controlled by movement of the other end of said strip to energize or de-energize said heat source, means for eilecting variation of temperature of said strip and means responsive to predetermined changes of steam and water conditions within said boiler to return said firstnamed means to or retain said first-named means in heat-source de-energizing position.

9. In a control device for a heating system in cluding a boiler and an electrically energized heat source, a resilient thermostat strip fixed at one end, means controlled by movement of the other end of said strip to energize and de-energize said heat source, a pivoted arm movable to return said control means to or retain said control means in heat source de-energizing position, a lever having one end connected to said arm, said lever being mounted for automatic swinging to bring said arm into heat source-de-energizing position, a latch normally engaging said lever to hold it out of its heat-source de-energizing .position, and means responsive to predetermined changes in steam and water conditions within said boiler to disengage said latch from said lever.

10. In a control device for a heating system including a boiler and an electrically energized heat source, a resilient thermostat strip fixed at one end, means for effecting variation of temperature of said strip, means controlled by movement of the other end of said strip to energize and deenergize said heat source, a pivoted arm movable to return said control means to or retain said control means in heat-source de-energizing position, a lever having one end connected to said arm, said lever being mounted for automatic swinging to bring said arm into heat-source deenergizing position, a pivoted cradle, a latch member carried by said cradle for engagement with said lever to maintain it out of heat-source de-energizing position, and means carried by said cradle in communication with said boiler for e1- fecting pivotal movement thereof responsive to changes of steam and water conditions within said boiler.

11. In a control device for a heating system in cluding a boiler and an electrically energized heat source, a resilient thermostat strip fixed at one 6 end, means controlled by movement of the other end of said strip to energize and de-energize said heat source, a pivoted arm movable to return said control means or retain the said control means in heat-source de-energizing position, a lever having one end connected to said arm, said lever being mounted for automatic swinging to bring said arm into heat source de-energizing position, a pivoted cradle, an arm pivoted to said cradle at a point removed from the cradle axis and having a portion at one end engageable with said lever to hold it in heat-source de-energizing position, stationary means engageable by the other end of said lever to efl'ect rotation thereof relative to said cradle, and means carried by said 20 cradle in communication with theinterior of said boiler for efiecting rocking of said cradle upon change of steam and water conditions in said boiler.

12. In a control device for a heating system 25 including a boiler and an electrically energized heat source, a resilient thermostat strip fixed at one end, means controlled by movement oi! the other end of said strip to energize and de-energlze said heat source, a heating circuit for said strip including a pair of stationary contacts and a heater coil, a bridging conductor movable into and out of bridging relation to said contacts in response to changes in steam and water conditions in said boiler, a shunt circuit around said contacts and heater coil including a second heater coil of higher resistance than said first heater coil, a normally open shunt circuit around said second heater coil and including signal means, and a thermostat strip associated with said second heater coil and adapted when heated to close said signal circuit.

13. In a control device for a heating system including a boiler and an electrically energized heat source, a resilient thermostat strip fixed at one end, means controlled by movement of the other end oi! said strip to energize and de-energize said heat source, means including a lever for returning said control means to or retaining the same in heat-source de-energizing position, said lever being mounted for automatic swinging into heat-source de-energizing position, means normally maintaining said lever out of heatsource de-energizing position and responsive to predetermined changes in steam and water conditions in said boiler to release said lever, and signal means actuated by movement of said lever into heat-source-deenergizing position.

14. In a control device for a heating system including a boiler and an electrically energized heat source, a resilient thermostat strip fixed at one end, means including a pair of spaced stationary contacts and a heater coil for effecting variation of the temperature of said strip, means controlled by the movement of the other end of said strip for energizing and de-energizing said heat source, a pivoted cradle, means carried by said cradle in communication with said boiler for effecting pivotal movement thereof responsive to changes of steam and water conditions within said boiler, and a bridging conductor carried by said cradle for movement into and out of bridging relation to said contacts.

15. In a control device for a heating system including a boiler and an electrically energized 75 heat source, a resilient thermostat strip fixed at one end, means including a pair 01' spaced stationary contacts and a heater coll for efiecting variation of the temperature oi. said strip, means controlled by the movement of the other end of said strip for energizing and de-energizing said heat source, a pivoted cradle, means carried by said cradle in communication with said boiler for eflecting pivotal movement thereof responsive to changes of steam and water conditions within said boiler, a bridging conductor carried by said cradle for movement into and out of bridging relation to said contacts, a shunt circuit around said contacts and heater coil including a second heater coil of higher resistance than said first heater coil, an open second shunt circuit around said second heater coil and including signal means, and a thermostat strip associated with said second heater coil and adapted, when heated, to close said signal circuit.

16. In a control device for a heating system including a boiler and an electrically energized heat source, a resilient thermostat strip fixed at one end, means including a pair of spaced stationary contacts and a heater coil for efiecting variation of the temperature of said strip, means controlled'by the movement of the other end of said strip for energizing and de-energizing said heat source, a pivoted cradle, means carried by said cradle incommunicatlon with said boiler for efiecting pivotal movement thereof responsive to changes of steam and water conditions within said boiler, a bridging conductor carried by said cradle for movement into and out of bridging relation to said contacts, means including a lever for returning said control means to or retaining the same in heat-source de-energized position, said lever being mounted for automatic swing ng into heat-source de-energized position, and means on said cradle normally engaging said lever to maintain it out of heat-source de-energized position and movable with said cradle to release said lever.

17. In a control device for a heating system including a boiler and an electrically energized heat source, a resilient thermostat strip fixed at one end, means including a pair of spaced stationary contacts and a heater coil for effectin variation of the temperature of said strip, means controlled by the movement of the other end of said strip for energizing and de-energizing said heat source, a pivoted cradle, means carried by said cradle in communication with said boiler for effecting pivotal movement thereof responsive to changes of steam and water conditions'within said boiler, a bridging conductor carried by said cradle for movement into and out of bridging relation to said contacts, a shunt circuit around said contacts and heater coil including a second heater coil of higher resistance than said first heater coil, an open second shunt circuit around said second heater coil and including signal means, a thermostat strip associated with said second heater coil and adapted, when heated, to close said signal circuit, means including a lever for returning said control means to or retaining the same in heat-source de-energized position, said lever being mounted for automatic swinging into heat-source de-energized position, and means on said cradle normally engaging said lever to maintain it out of heat-source de-energized position and movable with said cradle to release said lever.

18. A control device for an attemperating system including electrically energized means for producing temperature changes in an enclosed area, said device comprising a mercury switch tiltatably supported for gravity actuation into closed position, a rotatable arm adapted during each revolution to move said mercury switch to open position and release the same for automatic return to closed position, a driving motor for said arm, a motor-energizing circuit including a pair oi self-closing contacts, a carrier supporting said contacts and movable between two positions, an insulated member supported by thermally-responsive means arranged upon change of temperature to move said insulated membu between two positions corresponding to the two positions 01 said carrier, said insulated member being adapted when it and said carrier are in corresponding positions to open said contacts, temperature-controlled means for heating said thermally-responsive means, and means operated by said motor for moving said carrier between its two positions and for moving said insulated member out 01' contact-engaging position during movement of said carrier and releasing said insulated member for return to contact-open position, the actuation of said insulating member and carrier being timed to stop said arm twice during each complete revolution thereof and the arm in one position of rest holding said mercury switch in open position.

19. A control device for a heating system including a boiler and an electrically energized heat source, said device comprising a mercury switch tiltably supported for gravity actuation into closed position, a rotatable arm adapted during each revolution to move said mercury switch to open position and release the same for automatic return to closed position, a driving motor for said arm, a motor-energizing circuit including a pair of self-closing contacts, a carrier supporting said contacts and movable between two positions, an insulated member supported by thermally-responsive means arranged upon change of temperature to move said insulated member between two positions corresponding to the two positions of said carrier, said insulated member being adapted when it and said carrier are in corresponding positions to open said contacts, temperature-controlled means for heating said thermally-responsive means, means operated by said motor for moving said carrier between its two positions and for moving said insulated member out of contact-engaging position during movement of said carrier and releasing said insulated member for return to contact-open position, the actuation of said insulating member and carrier being timed to stop said arm twice during each complete revolution thereof and the arm in one position or rest holding said mercury switch in open position, and means responsive to predetermined changes of steam and water conditions within said boiler to return said insulated member to or hold said insulated member in the position in which it eflfects stoppage 01' said arm with the mercury switch in open position.

20. A control Qeviceior a heating system including a boiler and an electrically energized heat source, said device comprising a mercury switch tiltably supported for gravity actuation into closed position, a rotatable arm adapted during each revolution to move said mercury switch to open position and release the same for automatic return to closed position, a driving motor for said arm, a motor-energizing circuit including a pair of self-closing contacts, a carrier supporting said contacts and movable between two positions, an insulated member supported by thermally-responsive means arranged upon change of temperature to move said insulated member between two positions corresponding to the two positions of saidcarrier, said insulated member being adapted when it and said carrier are in corresponding positions to open said contacts, temperature-controlled means for heating said thermally-responsive means, means operated by said motor for moving said carrier between its two positions and for moving said insulated member out of contact-engaging position during movement of said carrier and releasing said insulated member for return to contact-open position, the actuation of said insulating member and carrier being timed to stop said arm twice during each complete revolution thereof and the arm in one position of rest holding said mercury switch in open position, means responsive to predetermined changes of steam and water conditions within said boiler to return said insulated member to or hold said insulated member in the position in which it eflects stoppage or said arm with the mercury switch in open position, and

signal means operated intermittently in response to slight changes of steam and water conditions in the. boiler and operated continuously in response to said predetermined changes of steam and water condition.

21. In a. control device for an attemperating system including an electrically energized attemperating source, a resilient thermostat strip fixed at one end, means controlled by movement of the other end of said strip to energize and de-energize said attemperating source, a heating circuit for said strip including a pair of stationary contacts and a heater coil, a bridging conductor movable into and out of bridging relation to said contacts in response to changes in conditions in said attemperating source, a shunt circuit around said contacts and heater coil including a second heater coil of higher resistance than said first heater coil, a normally open shunt circuit around said second heater coil, and including signal means, and a thermostat strip associated with said second heater coil and adapted when heated to close said signal circuit. HUBERT S. TURNER. 

